JP2007239801A - Angular contact ball bearing with seal - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an angular contact ball bearing with a seal capable of achieving improvement of durability and elongation of the life by increasing a grease sealing amount without increasing grease running-in time. <P>SOLUTION: This angular contact ball bearing with the seal is provided with an inner ring 1, an outer ring 2, a plurality of balls 3, a retainer 4, and seal members 7 and 8 fitted to seal grooves 5 and 6 formed on axial both ends of the outer ring 2. When an inside diameter dimension of the inner ring is (d) and an outside diameter dimension of the outer ring is D, the relationship between an axial cross section dimension X of the bearing and a radial cross section dimension (D-d)/2 of the bearing and a ball diameter Da is as follows; 1.2≤(X/Da)/ä(D-d)/2/Da}≤1.4. <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

  The present invention relates to a sealed angular contact ball bearing, and more particularly to a sealed angular contact ball bearing used for rotationally supporting a spindle of a machine tool.

In recent years, angular contact ball bearings that rotatably support the spindle of machine tools are used in a sealed angular contact ball bearing that is pre-sealed with grease and sealed with a seal from the viewpoint of extending the life of grease and assembling it into the spindle device. There is an increasing need (see, for example, Patent Document 1). In general, for angular contact ball bearings, standard bearing dimensions such as bearing inner diameter, bearing outer diameter, and bearing width are defined by the main dimensions of the international standard (ISO 15). Adopted. The JIS standard (JISB1522) is also consistent with this, and angular ball bearings are defined from the size range of commonly used bearings whose dimensional series is 19, 10, 02 and 03. In the above-mentioned sealed angular contact ball bearing, a bearing having this standard bearing size is used. In the bearing space between the inner ring and the outer ring surrounded by the seal member, for example, about 15 to 30% of the space volume. Of grease is enclosed.
JP 2003-42160 A

  By the way, in a conventional angular contact ball bearing with a seal, it is possible to improve the grease durability by enclosing a large amount of grease. However, when grease of about 30% of the space volume is encapsulated in the bearing space, the grease is not settled. Unfortunately, it takes a lot of time to run-in the grease.

  On the other hand, conventional angular contact ball bearings with seals may be used with a smaller cage width in order to avoid interference between the seal and the cage, or to increase the space volume for enclosing grease. The strength of the cage may be insufficient.

  The present invention has been made in view of the above circumstances, and an object of the present invention is to provide an angular ball with a seal that can increase the amount of grease filled without increasing the operating time of the grease and can improve durability. Provide bearings.

The above object of the present invention is achieved by the following configurations.
(1) An inner ring having an inner ring raceway surface on an outer peripheral surface, an outer ring having an outer ring raceway surface on an inner peripheral surface, and a plurality of balls arranged in a freely rollable manner between the outer ring raceway surface and the inner ring raceway surface; A sealed angular contact ball bearing comprising: a cage that holds the plurality of balls in the circumferential direction at predetermined intervals; and a seal member that is fitted in seal grooves formed at both axial ends of the outer ring. There,
When the inner diameter of the inner ring is d and the outer diameter of the outer ring is D, the relationship between the axial sectional dimension X of the bearing, the radial sectional dimension (Dd) / 2 of the bearing, and the ball diameter Da is ,
1.2 ≦ (X / Da) / {(D−d) / 2 / Da} ≦ 1.4
A sealed angular contact ball bearing characterized by being

  According to the sealed angular contact ball bearing of the present invention, the relationship between the axial sectional dimension X of the bearing, the radial sectional dimension (Dd) / 2 of the bearing, and the ball diameter Da is 1.2 ≦ (X / Da ) / {(D−d) / 2 / Da}, the standard bearing width dimension of the angular ball bearing is changed, and the axial sectional dimension is set larger than the radial sectional dimension of the bearing. As a result, the space volume for enclosing the grease can be made wider than before, and the absolute amount of the grease enclosure amount can be increased even if the ratio of the grease enclosure amount to the space volume is equal. By increasing the amount of grease, the grease life can be extended. Further, although the amount of grease filled increases, the space volume also increases, so that it is possible to avoid a prolonged break-in time. Further, by setting (X / Da) / {(D−d) / 2 / Da} ≦ 1.4, the grease is not increased unnecessarily, and the cost is improved.

  In addition, the inner diameter dimension d of the inner ring and the outer diameter dimension D of the outer ring may be configured such that the diameter series in the main dimension of ISO 15 has a relationship of 9 or 0. In this case, the main shaft, housing, etc. can be used as they are, and the bearing width does not become extremely wide.Therefore, when mounting, if the positional relationship of the bearing is adjusted with the outer ring spacer or inner ring spacer, etc. There is no need for major design changes. In addition, by expanding the bearing width, a standard cage can be used, the strength of the cage can be improved, and a ball guide cage can be adopted.

  DESCRIPTION OF EMBODIMENTS Hereinafter, an embodiment of a spindle apparatus in which a sealed angular ball bearing of the present invention is incorporated will be described with reference to the drawings.

  As shown in FIG. 1, in a spindle device 20 used in a machine tool, a spindle 21 is supported by a housing 22 via a sealed angular ball bearing 1 in which front and rear portions thereof are arranged in double rows. Each angular ball bearing 1 has two rows arranged with their backs facing each other (DBB combination).

  The inner peripheral surface of the housing 22 is a cylindrical surface, and has an inner flange portion 22A having a small diameter at an intermediate portion. The outer ring 3 of the front two rows of angular ball bearings 1 is arranged between the inner ring portion 22A of the housing 22 and the front lid 24 with an outer ring spacer 23 interposed therebetween, and the rear two rows of angular ball bearings 1 are arranged. The outer ring 3 of the angular ball bearing 1 is also disposed with an outer ring spacer 23 therebetween, with a predetermined gap between the inner flange 22A of the housing 22 and the rear lid 25.

  The main shaft 21 is provided with a tool holder attachment portion 21A at the front and a pulley attachment portion 21B at the rear, and steps 21C and 21D are provided at the front and intermediate portions so that the diameter gradually decreases toward the rear. It has been. The inner ring 2 of the two front rows of angular ball bearings 1 is provided with an inner ring spacer 26 therebetween, and a nut 27 that is screwed into a step 21C of the main shaft 21 and a male screw portion 21E formed on the main shaft 21. The inner ring 2 of the rear two rows of angular ball bearings 1 is also sandwiched between the inner ring 2 and a plurality of inner ring spacers 26 between the front and rear thereof, The main shaft 21 is fixed to the main shaft 21 in a clamped state by a nut 28 screwed into a male screw portion 21F formed on the main shaft 21.

  This sealed angular contact ball bearing 1 includes an inner ring 2 having an inner ring raceway surface 2a on the outer peripheral surface, an outer ring 3 having an outer ring raceway surface 3a on the inner peripheral surface, and a predetermined gap between the outer ring raceway surface 3a and the inner ring raceway surface 2a. A plurality of balls 4 which are arranged so as to be freely rotatable with a contact angle α, and a cage 5 which is guided by the plurality of balls 4 and holds the plurality of balls 4 in the circumferential direction at predetermined intervals. And non-contact seal members 8 and 9 fitted in seal grooves 6 and 7 formed at both axial ends of the outer ring 3.

  The inner diameter dimension d of the inner ring 2 and the outer diameter dimension D of the outer ring 3 are set so that the diameter series satisfies the relationship of 9 or 0 in the main dimensions of the international standard (ISO15). Further, when the axial sectional dimension (bearing width) of the sealed angular ball bearing 1 is X, the radial sectional dimension of the bearing 1 is (Dd) / 2, and the ball diameter is Da, Tables 1 and 2 show As shown, these relationships are: 1.2 ≦ (X / Da) / {(D−d) / 2 / Da} ≦ 1.4, preferably 1.2 ≦ (X / Da) / { (D−d) / 2 / Da} ≦ 1.3, and the axial sectional dimension X is larger and wider than the conventional axial sectional dimension X (see FIGS. 3 and 4). ). In particular, in the present embodiment, the bearing width X is set so that the width series is 2 in the main dimensions of the international standard (ISO 15) so that the manufacture can be performed simply. For example, when the diameter series is 9, the inner diameter d of the inner ring 2 is 70 mm, and the outer diameter D of the outer ring 3 is 100 mm, the ball diameter Da for the standard and ultra-high speed is 8.731 mm. When the major axis series is 0, the inner diameter d of the inner ring 2 is 70 mm, and the outer diameter D of the outer ring 3 is 110 mm, a standard ball diameter Da of 11.906 mm is used. The ball diameter Da is 8.731 mm.

  Here, if the value of (X / Da) / {(D−d) / 2 / Da} is made smaller than 1.2 (lower limit value), the bearing space cannot be made large, and the grease break-in operation takes time. Therefore, a sufficient amount of grease cannot be sealed. On the other hand, if it is larger than 1.4 (upper limit value), it is necessary to enclose a large amount of grease, which is not economical.

  For example, as shown in Tables 3 and 4, the ultra high speed sealed angular contact ball bearing 1 having a diameter series of 9 or 0 has a space volume ratio of 1.25 to 1. It can be 6 times. This makes it possible to increase the grease filling amount to 30% of the static space volume even when the running-in time is the same, which is 2.5 to 3 times that of the conventional product. Therefore, the grease life can be extended by increasing the amount of grease.

  In the sealed angular contact ball bearing 1 of the present embodiment, the spatial volume formed between the outer circumferential surface of the cage and the outer circumferential surface and the inner circumferential surface of the outer ring is 1. It is set to 2 to 1.6 times.

  Further, the sealed angular contact ball bearing 1 of the present invention may be a ball guide type retainer as in the present embodiment, or may be an outer ring guide type retainer. FIG. 3 (a) shows a comparison between the diameter series of 9 and the conventional ball guide method and the invention, and FIG. 3 (b) shows the diameter series of 9 and the outer ring guide type of the conventional product. The comparison with the invention is shown. FIG. 4 (a) shows a comparison between a conventional product with a diameter series of 0 and a ball guide system and an inventive product, and FIG. 4 (b) shows a comparison with a conventional product with a diameter series of 0 and an outer ring guide system. The comparison with the invention is shown.

  Therefore, in the sealed angular contact ball bearing 1 of the present embodiment, the relationship between the axial sectional dimension X of the bearing 1, the radial sectional dimension (Dd) / 2 of the bearing 1, and the ball diameter Da is 1.2 ≦ Since (X / Da) / {(Dd) / 2 / Da}, the dimension of the standard bearing width X in the angular ball bearing 1 is changed, and the axial cross section of the radial cross section of the bearing 1 is changed. The dimensions are set large. As a result, the space volume for enclosing the grease can be made wider than before, and the absolute amount of the grease enclosure amount can be increased even if the ratio of the grease enclosure amount to the space volume is equal. For example, when 30% of the space volume of grease is sealed in the bearing of the present invention, the absolute amount of the grease corresponds to 40% of the space volume of the conventional bearing. By increasing the amount of grease, the grease life can be extended. Further, although the amount of grease filled increases, the space volume also increases, so that it is possible to avoid a prolonged break-in time. Further, by setting (X / Da) / {(D−d) / 2 / Da} ≦ 1.4, the grease is not increased unnecessarily, and the cost is improved.

  In addition, since the inner diameter dimension d of the inner ring 2 and the outer diameter dimension D of the outer ring 3 have a relationship of 9 or 0 in the diameter series in the main dimensions of the ISO 15, the main shaft 21 and the housing 22 can be used as before. Since the bearing width is not extremely wide, it is sufficient to adjust the positional relationship of the bearing 1 with the outer ring spacer 23, the inner ring spacer 26, etc., and a large design change is not necessary. In addition, by expanding the bearing width, a standard cage can be used, the strength of the cage can be improved, and a ball guide cage can be adopted.

In addition, this invention is not limited to the said embodiment, In the range which does not deviate from the summary of this invention, it can change or improve suitably.
The spindle device to which the sealed angular ball bearing 1 of the present invention is applied is not limited to that shown in FIG. 1, but may be of a tool clamp type as shown in FIG. It is applicable to.

  For example, in the spindle device 30 shown in FIG. 5, a draw bar 32 in which a collet portion 32A for attaching a tool holder is formed at the front end of the hollow portion of the spindle 31 is forward and backward via an urging means 33 such as a disc spring. It is arranged to be movable. The main shaft 31 is rotatably supported by the housing 35 by the four rows of angular ball bearings 1 of the present invention disposed at the front and the double row cylindrical roller bearings 34 disposed at the rear. Also in the spindle device 30, the outer ring 3 of the angular ball bearing 1 is fixed between the small-diameter flange portion 35A of the housing 35 and the front lid 36 via an outer ring spacer 37. An inner ring spacer 38 is disposed therebetween, and is fixed to the main shaft 31 in a clamped state by a step 31A of the main shaft 31 and a nut 39 screwed into a male screw portion 31B formed on the main shaft 31.

It is a figure which shows the main axis | shaft apparatus in which the angular ball bearing with a seal | sticker of this invention is integrated. It is sectional drawing of the angular ball bearing with a seal | sticker of embodiment of this invention. (A) is a diagram showing a comparison between a ball bearing type conventional product and an invention product having a diameter series of 9 and an invention, and (b) is a diameter series of 9 and an outer ring guide type conventional product and invention. It is a figure which shows contrast with goods. (A) shows a comparison between the diameter series of 0 and the conventional product of the ball guide system and the invention, and (b) shows the conventional product and the invention of the outer ring guide system and the diameter series of 0. It is a figure which shows contrast with. It is a figure which shows the other spindle apparatus with which the angular ball bearing with a seal | sticker of this invention is integrated.

Explanation of symbols

2 Inner ring 2a Inner ring raceway surface 3 Outer ring 3a Outer ring raceway surface 4 Ball 5 Cage 6, 7 Seal groove 8, 9 Seal member

Claims (1)

An inner ring having an inner ring raceway surface on an outer peripheral surface, an outer ring having an outer ring raceway surface on an inner peripheral surface, a plurality of balls arranged in a freely rollable manner between the outer ring raceway surface and the inner ring raceway surface, An angular ball bearing with a seal, comprising: a cage that holds the balls of the outer ring at predetermined intervals in the circumferential direction; and seal members that are fitted into seal grooves formed at both axial ends of the outer ring,
Assuming that the inner diameter of the inner ring is d and the outer diameter of the outer ring is D, the relationship between the axial sectional dimension X of the bearing, the radial sectional dimension (Dd) / 2 of the bearing, and the ball diameter Da is ,
1.2 ≦ (X / Da) / {(D−d) / 2 / Da} ≦ 1.4
A sealed angular contact ball bearing characterized by being

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